Since the 1980s, electroluminescent (EL) technology has come into widespread use in display devices where its relatively low power consumption, relative brightness and ability to be formed in relatively thin-film configurations have shown it to be preferable to light emitting diodes (LEDs) and incandescent technologies for many applications.
Commercially manufactured EL devices have traditionally been produced using doctor blade coating and printing processes such as screen printing or, more recently, ink jet printing. For applications that require relatively planar EL devices these processes have worked reasonably well, as they lend themselves to high-volume production with relatively efficient and reliable quality control.
However, traditional processes are inherently self-limiting for applications where it is desirable to apply an EL device to a surface having complex contoured topologies, such as convex, concave and reflexed surfaces. Partial solutions have been developed wherein a relatively thin-film EL decal is applied to a surface, the decal being subsequently encapsulated within a polymer matrix. While moderately successful, this type of solution has several inherent weaknesses. Firstly, while decals can acceptably conform to mild concave/convex topologies, they are incapable of conforming to tight-radius curves without stretching or wrinkling. In addition, the decal itself does not form either a chemical or mechanical bond with an encapsulating polymer, essentially remaining a foreign object embedded within the encapsulating matrix. These weaknesses pose difficulties in both manufacturing and product life-cycle, as embedded-decal EL lamps applied to complex topologies are difficult to produce and are susceptible to delamination arising from mechanical stresses, thermal stresses and long-term exposure to ultraviolet (UV) light.